Computational model of abdominal aortic aneurysm inception and evolution
2014 (English)Licentiate thesis, comprehensive summary (Other academic)
Incidence of abdominal aortic aneurysm (AAA) is increasing in the aging society of the western world. Development of AAA is mostly asymptomatic and is characterized by a bulge in the abdominal aorta. However, AAA may suddenly rupture, which results in an internal bleeding associated with a high mortality rate. Patients with AAA undergo regular screening until treatment indication. To date, statistical criteria are used to decide whether the risk of rupture exceeds the risk of intervention. Models of AAA development help to understand the disease progression and to yield patient-speciﬁc criterion for AAA rupture.
Up to date, sophisticated models of AAA development exist. These models assume the abdominal aorta as a thin-walled structure, which saves the computational effort. This thesis aims at investigating the importance of employing a thick-walled model of the aorta. The effects on AAA development that cannot be captured with a thin-walled model are of interest. In Paper A, the thick-walled model of growth and remodeling of one layer of a AAA slice has been extended to a two-layered model. The parameter study has been performed to investigate the inﬂuence of mechanical properties and growth and remodeling (G&R) parameters of two individual layers on the gross mechanical response and G&R of the artery. It was concluded that the adventitia acts to protect the arterial wall against rupture even in pathological state.
In Paper B, the model was extended to an organ level model of AAA development. Furthermore, the model was incorporated into a so-called Fluid-Solid-Growth (FSG) framework, where the AAA development is loosely coupled to the blood ﬂow conditions such as wall shear stress. One patient-speciﬁc geometry of the abdominal aorta is used to illustrate the model capabilities. A transmurally non-uniform distribution of the strains of individual arterial constituents was observed. In addition, an increased aneurysm tortuosity was observed in comparison to a thin-walled approach. These ﬁndings signify the importance of a thick-walled approach to model the aneurysm development. Finally, the proposed methodology provides a realistic basis to further explore the growth and remodeling of AAA on a patient-speciﬁc basis.
Place, publisher, year, edition, pages
KTH Royal Institute of Technology, 2014. , viii, 8 p.
TRITA-HFL. Report / Royal Institute of Technology, Solid Mechanics, ISSN 1654-1472 ; 0553
aneurysm, three dimensional, elastin degradation, growth, remodeling, fluid-solid-growth model
Research subject Engineering Mechanics
IdentifiersURN: urn:nbn:se:kth:diva-142649ISBN: 978-91-7595-065-5OAI: oai:DiVA.org:kth-142649DiVA: diva2:703982
2014-03-19, Seminarierummet, Teknikringen 8d, KTH, Stockholm, 10:15 (English)
Hill, Nicholas, Professor
Gasser, T. Christian, Associate Professor
QC 201403112014-03-112014-03-102014-03-11Bibliographically approved
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